Wireless body area network transmission method and system

Abstract

The application provides a wireless body area network transmission method and system, which allocates subbands to each sensor according to the importance of obtaining physiological information and designs time-frequency codes; designs a physical layer security modulation and demodulation scheme based on multi-band orthogonal frequency division multiplexing ultra-wide band based on the channel state information of the legal link between each sensor and a digital assistant; each sensor dynamically adjusts the transmission scheme between it and the digital assistant according to the change of the channel state; the digital assistant allocates different antennas and receivers to each sensor respectively, and demodulates the corresponding physiological information based on the channel state information of the legal link; the digital assistant sends the personal medical information corresponding to the demodulated physiological information to a remote terminal. The application uses time-frequency codes, multi-band orthogonal frequency division multiplexing ultra-wide band modulation and physical layer security technology to deploy a safe and reliable wireless body area network transmission of multiple sensors, which can be used for wireless body area network eavesdropping prevention, internal interference elimination and transmission reliability improvement.

Description

Technical Field

[0001] This invention relates to physical layer security and multi-band orthogonal frequency division multiplexing ultra-wideband modulation technology in the field of wireless communication technology. Specifically, it relates to a wireless body area network transmission method and system based on time-frequency codes, physical layer security, and multi-band orthogonal frequency division multiplexing ultra-wideband modulation. Background Technology

[0002] Maintaining safe social distancing has gained wider public acceptance, and new online medical services are gradually emerging. Wireless Body Area Networks (WBANs) provide users with timely and personalized medical services through remote health monitoring, effectively ensuring safe social distancing.

[0003] Ultra-wideband (UWB) is one of the three physical layer transmission technologies for WBAN as defined by IEEE 802.15.6. Due to its noise-like characteristics, UWB signals do not cause harm to the human body, making them very suitable for WBAN communication. Multi-band Orthogonal Frequency Division Multiplexing Ultra-Wideband (MB-OFDM-UWB) is an excellent short-distance physical layer transmission technology that can provide reliable transmission with high speed, low power consumption, and low radiation for WBAN. MB-OFDM-UWB divides the entire frequency band into multiple sub-bands, and data transmission is performed on each sub-band using Orthogonal Frequency Division Multiplexing (OFDM) technology or improved OFDM technology. In the MB-OFDM-UWB modulation scheme, the transmitting and receiving ends transmit data on the designated sub-bands according to a pre-agreed time-frequency code.

[0004] Physical layer security (PLS) is a security mechanism applicable to WBANs. It utilizes various resources of the wireless channel and designs security policies based on the time-varying and reciprocal nature of the wireless channel to protect legitimate users. Common PLS techniques include carrier interleaving, constellation diagram rotation, adaptive constellation size adjustment, active antenna labeling, and artificial noise.

[0005] Building a secure and reliable wireless body area network (WBN) is crucial for telemedicine. However, existing WBNs face significant challenges such as severe channel fading, potential security vulnerabilities, and interference and access conflicts between sensors. Designing a reasonable system solution to effectively address these issues is a critical problem that urgently needs to be solved in the field of WBN communication.

[0006] Currently, no descriptions or reports of technologies similar to this invention have been found, and no similar information has been collected domestically or internationally. Summary of the Invention

[0007] To address the aforementioned shortcomings in the prior art, this invention provides a wireless body area network transmission method and system based on time-frequency codes, physical layer security, and multi-band orthogonal frequency division multiplexing ultra-wideband modulation.

[0008] According to one aspect of the present invention, a wireless body area network transmission method is provided, comprising:

[0009] Different sub-bands are assigned to each sensor used to acquire different physiological information according to the importance of the acquired physiological information, and time-frequency codes are designed based on the sub-bands assigned to each sensor.

[0010] Based on the channel state information of the legitimate links between each sensor and the digital assistant, a physical layer secure modulation and demodulation scheme based on multi-band orthogonal frequency division multiplexing ultrawideband is designed, and the acquired physiological information is transmitted between each sensor and the digital assistant.

[0011] The transmission scheme between each sensor and the digital assistant is dynamically adjusted based on changes in the channel conditions of the legitimate links between each sensor and the digital assistant, thereby optimizing the transmission of the corresponding physiological information.

[0012] The digital assistant assigns different antennas and receivers to each sensor, and demodulates the corresponding physiological information based on the channel state information of the legitimate link between the sensor and the digital assistant.

[0013] The personal medical information corresponding to the demodulated physiological information is sent to a remote terminal through a digital assistant, completing the wireless body area network transmission.

[0014] Preferably, the sensors are respectively arranged on the user's body surface or in the corresponding signal acquisition point; the digital assistant is arranged on the user's body; and the sensors and the digital assistant are distributed in a star topology.

[0015] Preferably, the step of assigning different sub-bands to each sensor used to acquire different physiological information according to the importance of the acquired physiological information, and designing time-frequency codes based on the sub-bands assigned to each sensor, includes:

[0016] Based on the importance of the physiological information acquired by each sensor, sub-bands are assigned to each sensor until all sub-bands are assigned; the assigned sub-bands are used for information transmission between the sensors and the digital assistant;

[0017] Each sensor is assigned a sub-band, and each sensor is designed with a time-frequency code that is either non-overlapping or distinct.

[0018] Based on the importance of the physiological information collected by each sensor, as well as the transmission rate and bit error rate of each sensor, a separate transmission mode is set on each subband of each sensor to obtain the maximum safe transmission rate.

[0019] Preferably, the design of a physical layer secure modulation and demodulation scheme based on multi-band orthogonal frequency division multiplexing ultrawideband, based on channel state information of legitimate links between each sensor and the digital assistant, includes:

[0020] By combining any physical layer security technology with multi-band orthogonal frequency division multiplexing ultra-wideband, a physical layer secure modulation and demodulation scheme can be obtained.

[0021] Preferably, the physical layer security technology includes: carrier interleaving and / or artificial noise.

[0022] Preferably, the carrier interleaving method is combined with multi-band orthogonal frequency division multiplexing ultrawideband, including:

[0023] Within each subband, the transmitting end uses the channel state information of each carrier in the legitimate link to complete carrier interleaving in the order of the magnitude of the channel coefficients. The legitimate receiving end has the same channel state information as the transmitting end, so it can obtain the carrier interleaving order and deinterleave, thereby obtaining the information transmitted by each carrier. The illegitimate receiving end cannot obtain the channel state information of the legitimate link, so it cannot eliminate the interference of carrier interleaving, thus obtaining the physical layer secure modulation and demodulation scheme.

[0024] Preferably, the method combines artificial noise with multi-band orthogonal frequency division multiplexing ultrawideband, including:

[0025] Within each subband, the transmitting end generates artificial noise using the channel state information of each carrier in the legitimate link. The legitimate receiving end has the same channel state information as the transmitting end, thus eliminating the artificial noise and obtaining the information transmitted by the transmitting end. The illegitimate receiving end, unable to obtain the channel state information of the legitimate link, is unable to eliminate the interference of artificial noise, thus obtaining a physical layer secure modulation and demodulation scheme.

[0026] Preferably, the transmission scheme includes: a transmitter-side scheme and a receiver-side scheme; wherein:

[0027] The transmitter-side scheme includes: applying a modulation scheme based on MB-OFDM-UWB combined with carrier interleaving or artificial noise to the sensor transmitter; wherein, firstly, according to the sub-bands allocated by the time-frequency code, carrier interleaving or artificial noise is performed in each sub-band based on the channel state information of the legitimate link; secondly, one information symbol is transmitted each time using OFDM modulation in each sub-band; if a physical layer security scheme of carrier interleaving is adopted, the information symbol is transmitted through the interleaved carrier; if a physical layer security scheme of artificial noise is adopted, the generated noise is superimposed on the transmitted information symbol and transmitted together.

[0028] The receiver-side scheme includes: applying a demodulation scheme based on MB-OFDM-UWB combined with decarrier interleaving or artificial noise removal to the receiver of a digital assistant; wherein, using the same time-frequency code as the transmitter, demodulation is performed on pre-agreed sub-bands; firstly, decarrier interleaving or artificial noise removal is performed in each sub-band according to the channel state information of the legitimate link; then, OFDM demodulation is performed in each sub-band to obtain the transmitted information symbols.

[0029] Preferably, dynamically adjusting the transmission scheme includes:

[0030] Based on the required transmission rate and bit error rate of each sensor, the transmission scheme of each sensor in its respective subband is dynamically adjusted to maximize its safe transmission rate. The transmission scheme includes: constellation size, carrier interleaving scheme and / or energy distribution ratio of artificial noise to information.

[0031] According to another aspect of the present invention, a wireless body area network transmission system is provided, comprising:

[0032] Subband allocation module, which is used to allocate different subbands to each sensor according to the importance of acquiring physiological information, and design time-frequency codes based on the subbands allocated to each sensor;

[0033] The modulation design and optimization module designs a physical layer secure modulation and demodulation scheme based on multi-band orthogonal frequency division multiplexing ultrawideband based on the channel state information of the legitimate links between each sensor and the digital assistant, and transmits the acquired physiological information between each sensor and the digital assistant; it dynamically adjusts the transmission scheme between each sensor and the digital assistant according to the changes in the channel state of the legitimate links between each sensor and the digital assistant, and optimizes the transmission of the corresponding physiological information.

[0034] The information demodulation module uses a digital assistant to assign different antennas and receivers to each sensor, and demodulates the corresponding physiological information based on the channel state information of the legitimate link between the sensor and the digital assistant.

[0035] The external transmission module sends the personal medical information corresponding to the demodulated physiological information to the remote terminal through the digital assistant, completing the wireless body area network transmission.

[0036] By adopting the above technical solution, the present invention has at least one of the following beneficial effects compared with the prior art:

[0037] The wireless body area network transmission method and system provided by this invention utilize time-frequency codes and multi-band orthogonal frequency division multiplexing ultra-wideband physical layer secure modulation to deploy secure and reliable wireless body area network transmission for multiple sensors. By designing an effective communication mechanism between each sensor and the digital assistant, the system effectively manages various physical layer resources, fully considers the importance of different physiological information, flexibly sets the priority of information transmission, and establishes an adaptive allocation mechanism to dynamically adjust various physical layer resources to maximize the performance of the system in all aspects.

[0038] The wireless body area network transmission method and system provided by this invention organically combine multi-band orthogonal frequency division multiplexing ultra-wideband, time-frequency coding and physical layer security technologies. By introducing physical layer security technology through multi-band orthogonal frequency division multiplexing ultra-wideband modulation, a physical layer secure transmission strategy is proposed to ensure the security and reliability of legitimate user medical data transmission. Attached Figure Description

[0039] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0040] Figure 1 This is a flowchart illustrating the workflow of a wireless body area network transmission method in a preferred embodiment of the present invention.

[0041] Figure 2 This is a schematic diagram of an eavesdropping model for wireless body area network communication in a preferred embodiment of the present invention.

[0042] Figure 3 This is a schematic diagram of the components of a wireless body area network transmission system in a preferred embodiment of the present invention. Detailed Implementation

[0043] The embodiments of the present invention are described in detail below: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0044] Wireless Body Area Networks (WBANs) are a communication technology that enables long-distance health monitoring, effectively ensuring social distancing. However, existing WBANs typically suffer from severe fading, potential eavesdropping risks, and internal interference. One embodiment of this invention addresses these issues by providing a WBAN transmission method. This method, starting from physical layer security, organically combines multi-band orthogonal frequency division multiplexing ultra-wideband (MB-OFDM-UWB), time-frequency coding, and physical layer security technologies. It utilizes MB-OFDM-UWB modulation to introduce physical layer security technology and proposes a physical layer secure transmission strategy, thereby ensuring the security and reliability of legitimate users' medical data transmission.

[0045] Specifically, such as Figure 1 As shown, the wireless body area network transmission method provided in this embodiment may include the following operations:

[0046] S1. Assign different sub-bands to each sensor used to acquire different physiological information according to the importance of acquiring physiological information, and design time-frequency codes based on the sub-bands assigned to each sensor.

[0047] S2, based on the channel state information of the legitimate links between each sensor and the digital assistant, design a physical layer secure modulation and demodulation scheme based on multi-band orthogonal frequency division multiplexing ultra-wideband, and transmit the acquired physiological information between each sensor and the digital assistant;

[0048] S3, dynamically adjust the transmission scheme between each sensor and the digital assistant according to the changes in the channel conditions of the legitimate link between each sensor and the digital assistant, and optimize the transmission of the corresponding physiological information;

[0049] S4. The digital assistant assigns different antennas and receivers to each sensor and demodulates the corresponding physiological information based on the channel state information of the legitimate link between the sensor and the digital assistant.

[0050] S5 uses a digital assistant to send the personal medical information corresponding to the demodulated physiological information to a remote terminal via the Internet or mobile network, completing the wireless body area network transmission.

[0051] In some preferred embodiments, the sensors can be respectively arranged on the corresponding signal acquisition points on the user's body surface or inside the body; the digital assistant can be arranged on the user's body; and the sensors and the digital assistant are distributed in a star topology.

[0052] In some preferred embodiments, S1 above, which assigns different sub-bands to each sensor used to acquire different physiological information according to the importance of the acquired physiological information, and designs time-frequency codes based on the sub-bands assigned to each sensor, may further include:

[0053] S11. Based on the importance of the physiological information acquired by each sensor, sub-bands are assigned to each sensor. Among them, sensors with important information in the classification are assigned multiple sub-bands, sensors with less important information in the classification are assigned sub-bands, and so on, until all sub-bands are assigned. The assigned sub-bands are used for information transmission between the sensors and the digital assistant.

[0054] S12, design time-frequency codes for each sensor that are non-overlapping or different based on the sub-bands allocated to each sensor;

[0055] S13, based on the importance of the physiological information collected by each sensor and the transmission rate and bit error rate of each sensor, set the transmission mode on each sub-band of each sensor to obtain the maximum safe transmission rate.

[0056] In some preferred embodiments, S2 above, which designs a physical layer secure modulation and demodulation scheme based on multi-band orthogonal frequency division multiplexing ultra-wideband based on the channel state information of the legitimate links between each sensor and the digital assistant, may further include:

[0057] S21, by combining any one of the physical layer security technologies with multi-band orthogonal frequency division multiplexing ultra-wideband, a physical layer security modulation and demodulation scheme is obtained.

[0058] In some preferred embodiments, the physical layer security technology described in S21 may further include: carrier interleaving and / or artificial noise.

[0059] In some preferred embodiments, the above-mentioned S21 can be combined with carrier interleaving and multi-band orthogonal frequency division multiplexing ultra-wideband, and may further include:

[0060] Within each subband, the transmitting end utilizes the channel state information of each carrier in the legitimate links (links between each sensor and the digital assistant) to complete carrier interleaving in order of magnitude of the channel coefficients. The legitimate receiving end has the same channel state information as the transmitting end, thus enabling it to obtain the carrier interleaving order for deinterleaving and thereby obtain the information transmitted by each carrier. The illegitimate receiving end, unable to obtain the channel state information of the legitimate links, is unable to eliminate the interference of carrier interleaving, thus obtaining a physical layer secure modulation and demodulation scheme.

[0061] In some preferred embodiments, the above-mentioned S21 can be combined with artificial noise method and multi-band orthogonal frequency division multiplexing ultra-wideband, and may further include:

[0062] Within each subband, the transmitting end generates artificial noise using the channel state information of each carrier in the legitimate link. The legitimate receiving end has the same channel state information as the transmitting end, thus effectively eliminating the artificial noise and obtaining the information transmitted by the transmitting end. The illegitimate receiving end, unable to obtain the channel state information of the legitimate link, is unable to eliminate the interference of artificial noise, thus obtaining a physical layer secure modulation and demodulation scheme.

[0063] In some preferred embodiments, the above-mentioned S3 transmission scheme may further include: a transmitter-side scheme and a receiver-side scheme; wherein:

[0064] The transmitter-side scheme includes: applying a modulation scheme based on MB-OFDM-UWB combined with carrier interleaving or artificial noise to the sensor transmitter; wherein, firstly, according to the sub-bands allocated by the time-frequency code, carrier interleaving or artificial noise is performed in each sub-band based on the channel state information of the legitimate link; secondly, one information symbol is transmitted at a time using OFDM modulation in each sub-band; if a physical layer security scheme of carrier interleaving is adopted, the information symbol is transmitted through the interleaved carrier; if a physical layer security scheme of artificial noise is adopted, the generated noise is superimposed on the transmitted information symbol and transmitted together.

[0065] The receiver-side solution includes: applying a demodulation scheme based on MB-OFDM-UWB combined with decarrier interleaving or artificial noise removal to the receiver of a digital assistant; wherein, the same time-frequency code as the transmitter is used, and demodulation is performed on pre-agreed sub-bands respectively; first, decarrier interleaving or artificial noise removal is performed in each sub-band according to the channel state information of the legitimate link; then, OFDM demodulation is performed in each sub-band to obtain the transmitted information symbols.

[0066] In some preferred embodiments, the above-mentioned S3, dynamically adjusting the transmission scheme, may further include:

[0067] Based on the required transmission rate and bit error rate of each sensor, the transmission scheme of each sensor in its respective subband is dynamically adjusted to maximize its safe transmission rate. The transmission scheme includes: constellation size, carrier interleaving scheme and / or energy distribution ratio of artificial noise to information.

[0068] The technical solutions provided by the above embodiments of the present invention will be further described in detail below with reference to a specific application.

[0069] Step 1: Classify various sensors located on or inside the body according to the importance of the physiological information they collect, assign subbands to each sensor, and design time-frequency codes based on the subbands assigned to each sensor; wherein:

[0070] Step 1.1: Distribute the sensor AI nodes and the digital assistant Bob using a star topology. Further, the user may have sensors for EEG, ECG, blood pressure, blood sugar, body temperature, and motion detection, located in the head, heart, fingertips, left arm, wrist, and ankle, respectively. The digital assistant (PDA) is located in the waist and abdomen, while the eavesdropper Eve is located externally. This arrangement is as follows: Figure 2 As shown.

[0071] Step 1.2: When allocating sub-bands according to the importance of the information collected by the sensors, sensors collecting important information can be assigned multiple sub-bands, and less important sensors can be assigned sub-bands, until all sub-bands are allocated. After allocation, each sensor transmits information to the digital assistant through its assigned sub-band.

[0072] Step 1.3: Design non-overlapping or different time-frequency codes for each sensor based on the sub-band assigned to each sensor. These time-frequency codes are used to implement the application of the sub-band assigned to each sensor.

[0073] Step 2: Each sensor collects different physiological information. Based on the channel state information of the legitimate link between the sensor and the digital assistant, a physical layer secure modulation scheme based on multi-band orthogonal frequency division multiplexing ultra-wideband (MB-OFDM-UWB) is designed and the collected information is transmitted; wherein:

[0074] Step 2.1, the physical layer security modulation scheme based on MB-OFDM-UWB modulation design is obtained by combining any one of the physical layer security technologies such as carrier interleaving and artificial noise with MB-OFDM-UWB.

[0075] Step 2.2: Based on the importance, transmission rate, and bit error rate of the medical information collected by the sensor, set specific transmission modes (modulation methods and physical layer security technologies) on each subband to obtain the maximum secure transmission rate.

[0076] Step 3: Based on the time-varying characteristics of the channel and the errors in channel estimation, each sensor dynamically adjusts the transmission scheme between the sensor and the digital assistant to ensure the secure and reliable transmission of various types of data.

[0077] In steps 2 and 3, due to the reciprocity of the channel, only the legitimate receiver can obtain the same channel state information as the transmitter. The transmitter (sensor Alice) uses the consistent channel state information from the legitimate channel (the link between Alice and Bob) to design a physical layer secure transmission scheme, ensuring that it does not affect the legitimate receiver (digital assistant Bob)'s information reception, while simultaneously impacting the eavesdropper (Eve). This is to prevent eavesdropping.

[0078] Step 4: The digital assistant assigns a different antenna and receiver to each sensor, allowing it to process information from different sensors simultaneously and eliminating interference between them. Based on channel reciprocity, the digital assistant successfully demodulates the transmitted medical data. Meanwhile, the eavesdropper, unable to obtain the channel state information of the legitimate link, is unable to demodulate the transmitted information.

[0079] Step 5: After the digital assistant retrieves the information carried by each sensor, it sends the information to the remote medical analysis center via the Internet or mobile network, ultimately providing patients with accurate and personalized medical services.

[0080] The wireless body area network transmission method provided in the above embodiments of the present invention utilizes time-frequency codes, multi-band orthogonal frequency division multiplexing ultra-wideband modulation, and physical layer security technology to deploy secure and reliable wireless body area network transmission for multiple sensors. It can be used for wireless body area network anti-eavesdropping, elimination of internal interference, and improvement of transmission reliability.

[0081] One embodiment of the present invention provides a wireless body area network transmission system.

[0082] Specifically, such as Figure 3 As shown, the wireless body area network transmission system provided in this embodiment may include the following modules:

[0083] Subband allocation module, which is used to allocate different subbands to each sensor according to the importance of acquiring physiological information, and design time-frequency codes based on the subbands allocated to each sensor;

[0084] The modulation design and optimization module designs a physical layer secure modulation and demodulation scheme based on multi-band orthogonal frequency division multiplexing ultrawideband based on the channel state information of the legitimate links between each sensor and the digital assistant, and transmits the acquired physiological information between each sensor and the digital assistant; it dynamically adjusts the transmission scheme between each sensor and the digital assistant according to the changes in the channel state of the legitimate links between each sensor and the digital assistant, and optimizes the transmission of the corresponding physiological information.

[0085] The information demodulation module uses a digital assistant to assign different antennas and receivers to each sensor, and demodulates the corresponding physiological information based on the channel state information of the legitimate link between the sensor and the digital assistant.

[0086] The external transmission module sends the personal medical information corresponding to the demodulated physiological information to the remote terminal through the digital assistant, completing the wireless body area network transmission.

[0087] The wireless body area network transmission system provided in the above embodiments of the present invention operates as follows:

[0088] Various sensors located on or inside the body are classified according to the importance of the physiological information they collect, and subbands are assigned to each sensor. Time-frequency codes are designed based on the assigned subbands.

[0089] Each sensor collects different physiological information. Based on the channel state information of the legitimate link between the sensor and the data assistant, a physical layer secure modulation scheme based on MB-OFDM-UWB is designed and the collected information is transmitted. Considering the time-varying characteristics of the human body channel and the errors in channel estimation, each sensor needs to dynamically adjust its transmission scheme with the data assistant to ensure the secure and reliable transmission of all types of data.

[0090] The digital assistant assigned different antennas and receivers to each sensor and successfully demodulated the medical data based on channel reciprocity.

[0091] After retrieving the information carried by the sensors, the data-assisted analysis system sends the information to a remote medical analysis center via the Internet or mobile network, ultimately providing patients with accurate and personalized medical services.

[0092] It should be noted that the steps in the method provided by the present invention can be implemented using corresponding modules, devices, units, etc. in the system. Those skilled in the art can refer to the technical solution of the method to realize the composition of the system. That is, the embodiments in the method can be understood as preferred examples for building the system, and will not be elaborated here.

[0093] The wireless body area network (BNB) transmission method and system provided by this invention utilizes time-frequency coding and multi-band orthogonal frequency division multiplexing (OFDM) ultra-wideband physical layer secure modulation to deploy secure and reliable wireless BNB transmission for multiple sensors. By designing an effective communication mechanism between each sensor and the digital assistant, it effectively manages various physical layer resources, fully considers the importance of different physiological information, flexibly sets the priority of information transmission, and establishes an adaptive allocation mechanism to dynamically adjust various physical layer resources to maximize system performance. It organically combines OFDM ultra-wideband, time-frequency coding, and physical layer security technologies, introducing physical layer security technology through OFDM ultra-wideband modulation, and proposes a physical layer secure transmission strategy to ensure the security and reliability of legitimate user medical data transmission.

[0094] Any matters not covered in the above embodiments of the present invention are well-known in the art.

[0095] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A wireless body area network transmission method, characterized in that, include: Different sub-bands are assigned to each sensor used to acquire different physiological information according to the importance of the acquired physiological information, and time-frequency codes are designed based on the sub-bands assigned to each sensor. Based on the channel state information of the legitimate links between each sensor and the digital assistant, a physical layer secure modulation and demodulation scheme based on multi-band orthogonal frequency division multiplexing ultrawideband is designed, and the acquired physiological information is transmitted between each sensor and the digital assistant. The transmission scheme between each sensor and the digital assistant is dynamically adjusted based on changes in the channel conditions of the legitimate links between each sensor and the digital assistant, thereby optimizing the transmission of the corresponding physiological information. The digital assistant assigns different antennas and receivers to each sensor, and demodulates the corresponding physiological information based on the channel state information of the legitimate link between the sensor and the digital assistant. The personal medical information corresponding to the demodulated physiological information is sent to the remote terminal through the digital assistant, completing the wireless body area network transmission; The process of assigning different sub-bands to each sensor used to acquire different physiological information according to the importance of the acquired physiological information, and designing time-frequency codes based on the sub-bands assigned to each sensor, includes: Based on the importance of the physiological information acquired by each sensor, sub-bands are assigned to each sensor until all sub-bands are assigned; the assigned sub-bands are used for information transmission between the sensors and the digital assistant; Each sensor is assigned a sub-band, and each sensor is designed with a time-frequency code that is either non-overlapping or distinct. Based on the importance of the physiological information collected by each sensor, as well as the transmission rate and bit error rate of each sensor, a separate transmission mode is set on each subband of each sensor to obtain the maximum safe transmission rate.

2. The wireless body area network transmission method according to claim 1, characterized in that, The sensors are respectively arranged on the user's body surface or in the corresponding signal collection points; the digital assistant is arranged on the user's body; the sensors and the digital assistant are distributed in a star topology.

3. The wireless body area network transmission method according to claim 1, characterized in that, Based on the channel state information of the legitimate links between each sensor and the digital assistant, a physical layer secure modulation and demodulation scheme based on multi-band orthogonal frequency division multiplexing ultra-wideband is designed, including: By combining any physical layer security technology with multi-band orthogonal frequency division multiplexing ultra-wideband, a physical layer secure modulation and demodulation scheme can be obtained.

4. The wireless body area network transmission method according to claim 3, characterized in that, The physical layer security technologies include: carrier interleaving and / or artificial noise.

5. The wireless body area network transmission method according to claim 3 or 4, characterized in that, The method combines carrier interleaving with multi-band orthogonal frequency division multiplexing (OFDM) ultrawideband, including: Within each subband, the transmitting end utilizes the channel state information of each carrier in the legitimate link to complete carrier interleaving in the order of the magnitude of the channel coefficients. The legitimate receiving end has the same channel state information as the transmitting end, thus enabling it to obtain the carrier interleaving order for deinterleaving and obtain the information transmitted by each carrier. However, the illegitimate receiving end cannot obtain the channel state information of the legitimate link, thus failing to eliminate the interference of carrier interleaving, resulting in a physical layer secure modulation and demodulation scheme. The method combines artificial noise with multi-band orthogonal frequency division multiplexing (OFDM) ultrawideband, including: Within each subband, the transmitting end generates artificial noise using the channel state information of each carrier in the legitimate link. The legitimate receiving end has the same channel state information as the transmitting end, thus eliminating the artificial noise and obtaining the information transmitted by the transmitting end. The illegitimate receiving end, unable to obtain the channel state information of the legitimate link, is unable to eliminate the interference of artificial noise, thus obtaining a physical layer secure modulation and demodulation scheme.

6. The wireless body area network transmission method according to claim 1, characterized in that, The transmission scheme includes: a transmitter-side scheme and a receiver-side scheme; wherein: The transmitter-side scheme includes: applying a modulation scheme based on MB-OFDM-UWB combined with carrier interleaving or artificial noise to the sensor transmitter; wherein, firstly, according to the sub-bands allocated by the time-frequency code, carrier interleaving or artificial noise is performed in each sub-band based on the channel state information of the legitimate link; secondly, one information symbol is transmitted each time using OFDM modulation in each sub-band; if a physical layer security scheme of carrier interleaving is adopted, the information symbol is transmitted through the interleaved carrier; if a physical layer security scheme of artificial noise is adopted, the generated noise is superimposed on the transmitted information symbol and transmitted together. The receiver-side scheme includes: applying a demodulation scheme based on MB-OFDM-UWB combined with decarrier interleaving or artificial noise removal to the receiver of a digital assistant; wherein, using the same time-frequency code as the transmitter, demodulation is performed on pre-agreed sub-bands; firstly, decarrier interleaving or artificial noise removal is performed in each sub-band according to the channel state information of the legitimate link; then, OFDM demodulation is performed in each sub-band to obtain the transmitted information symbols.

7. The wireless body area network transmission method according to claim 6, characterized in that, Dynamically adjusting the transmission scheme includes: Based on the required transmission rate and bit error rate of each sensor, the transmission scheme of each sensor in its respective subband is dynamically adjusted to maximize its safe transmission rate. The transmission scheme includes: constellation size, carrier interleaving scheme and / or energy distribution ratio of artificial noise to information.

8. A wireless body area network transmission system, characterized in that, include: Subband allocation module, which is used to allocate different subbands to each sensor according to the importance of acquiring physiological information, and design time-frequency codes based on the subbands allocated to each sensor; The modulation design and optimization module designs a physical layer secure modulation and demodulation scheme based on multi-band orthogonal frequency division multiplexing ultrawideband based on the channel state information of the legitimate links between each sensor and the digital assistant, and transmits the acquired physiological information between each sensor and the digital assistant. The transmission scheme between each sensor and the digital assistant is dynamically adjusted based on changes in the channel conditions of the legitimate links between each sensor and the digital assistant, thereby optimizing the transmission of the corresponding physiological information. The information demodulation module uses a digital assistant to assign different antennas and receivers to each sensor, and demodulates the corresponding physiological information based on the channel state information of the legitimate link between the sensor and the digital assistant. The external transmission module sends the personal medical information corresponding to the demodulated physiological information to the remote terminal through the digital assistant, completing the wireless body area network transmission; The process of assigning different sub-bands to each sensor used to acquire different physiological information according to the importance of the acquired physiological information, and designing time-frequency codes based on the sub-bands assigned to each sensor, includes: Based on the importance of the physiological information acquired by each sensor, sub-bands are assigned to each sensor until all sub-bands are assigned; the assigned sub-bands are used for information transmission between the sensors and the digital assistant; Each sensor is assigned a sub-band, and each sensor is designed with a time-frequency code that is either non-overlapping or distinct. Based on the importance of the physiological information collected by each sensor, as well as the transmission rate and bit error rate of each sensor, a separate transmission mode is set on each subband of each sensor to obtain the maximum safe transmission rate.

Images